Usability

The characteristic of being easy to use, usually applied to software, but relevant to almost any human artifact. What makes an artifact easy to use? Broadly, something is easy to use to the extent that it effectively performs the task for which it is being used. Ease of use can be measured by how quickly a task is performed, how many mistakes are made, how quickly the system is learned and how satisfied people are who perform the task. Usability may also include factors such as safety, usefulness, and cost-effectiveness.